Three Austrian men have had a disabled hand replaced with a bionically reconstructed hand. The new hands can be controlled using nerves and muscles that were transplanted into their arms from their legs. The replacement involved amputating their injured hands.
The bionic hands respond to faint signals from the transplanted nerves and muscles and open and close them. Other types of bionic hands are controlled primarily with manual settings.
The type of injury all three men had is called a global brachial plexus injury. The brachial plexus is the network of nerves that run from the spinal cord down the arm and control the arm and hand. A global injury to this nerve network renders the hand limp and useless.
The hand replacement took part in two stages. The first stage was to indentify and create useful electrical signals from the muscles so that the prosthetic hand could be controlled. Patients went through a tailored rehabilitation program where they wore the prostheses alongside their natural hand so that these signals were enhanced and the patients learned to control them. In the second stage, the natural hand was amputated and the patients were fitted with the prosthetic.
The reconstruction was successful in all three patients and all three gained useful function. They were able to use their prostheses better than they had been able to use the hands that were amputated. The report on these cases was published online in The Lancet, which includes a video of one of the men before, during, and after the reconstruction (http://www.thelancet.com/journals/laninf/article/PIIS0140-6736(14)61776-1/fulltext). The man could not manipulate objects such as a ball or a coin with his natural hand before the surgery and was able to do so with the prosthesis during his training to use the prosthesis and after the surgery.